Vfc

2 definitions found

From Virtual Entity of Relevant Acronyms (Version 1.9, June 2002) [vera]:

  VFC
       V. Fast Class (MODEM), "V.FC"
       
       

From The Free On-line Dictionary of Computing (27 SEP 03) [foldoc]:



  V.FC
       
           A serial line {protocol} supported
          by some {modems}.  Uses {symbol rates} of 2400, 2800, 3000,
          >3200 and 3429 and up to 28800 {baud}.
       
          {V.34} modems will also support V.FC if the manufacturer
          currently supports V.FC.
       
          The first V.FC modems were shipped in November 1993 and there
          have been many thousands sold.  There will probably be in
          excess of a million V.FC modems installed by the end of 1994.
       
          V.FC was intended to take some of the techniques being
          proposed for V.34 and put them into a real modem that people
          could use.  This also gave a lot of people the opportunity to
          try out 28.8 kilobit per second operation for the first time.
          There was never any intention from {Hayes} or {Rockwell} (who
          worked together for two years on V.FC) that V.FC would be
          compatible with V.34 - even if they had wanted it, others
          would have made sure it didn't happen!  In fact, they made the
          start-up deliberately different from V.34 so that it would be
          easy to distinguish between the two and easier to make
          dual-mode V.FC/V.34 modems.
       
          V.FC is quite different from V.34.  Most of the
          signal-processing {algorithm}s, whilst based on the same
          theory, are implemented in different ways.  V.34 has some
          extra things like a {secondary channel} and a special mode for
          28.8 kilobit per second fax.
       
          The Rockwell V.FC implementation uses a single-chip
          mask-programmed {DSP} for all the signal processing functions.
          You can also buy a modem controller chip from Rockwell to go
          with it which implements AT commands, error-control and
          {compression}.  Hayes made their own controller using the
          {Motorola} {68302} processor.  When it comes to an upgrade
          from V.FC to V.34 you have to have a new, masked DSP chip and
          new controller {firmware} to implement all the V.34-specific
          features.  This means that Rockwell-DSP based modems must be
          returned to the manufacturer for upgrade.  Upgraded modems
          will talk to either V.FC or V.34 modems.